ISLAMABAD — The attack on Karachi's airport — Pakistan's busiest — killed 19 security personnel and civilians, along with the 10 assailants. The group that claimed responsibility Monday vowed even more violence. Here are the issues related to the history of militancy in Pakistan:

Who are the Pakistani Taliban and what do they want?

The Pakistani Taliban, formally known as Tehrik-e-Taliban Pakistan, was formed in 2007 when various militant groups already operating in the country's northwest banded together. The group aims to overthrow the government and impose a hard-line form of Islam. It also has called on the government to pull all troops from tribal areas bordering Afghanistan where many of the militant groups are based. The TTP is loosely affiliated with the Afghan Taliban, which is fighting U.S.-led forces in Afghanistan, and shares similar ideology, but it has a different leadership structure. The TTP focuses its fight in Pakistan.

What does this attack mean for the peace process?

The attack raises serious doubts about the feasibility of continuing negotiations with the militants. The government of Prime Minister Nawaz Sharif has yet to say that it is abandoning talks altogether. The U.S. has said the negotiations are an internal matter but the U.S. has previously pushed for a military operation in North Waziristan, since many militant groups use the area as a base to attack Afghanistan. The U.S. is believed to question the likelihood of talks leading to the Pakistani Taliban disarming.

Is the Pakistani military making any headway against the Taliban?

Pakistan has been carrying out large-scale military operations in the northwest since 2009, when it launched an operation to retake the Swat Valley, a heavily populated area that had been taken over by Taliban militants. That was followed by operations in other regions along the Afghan border that have displaced hundreds of thousands of civilians and killed more than 4,000 Pakistani troops. North Waziristan is the only region where the military has not carried out a large operation so far, and it has become a hub for militant groups.

How do Pakistanis feel about the Taliban and the attacks?

Pakistanis are tired of the violence and the government's seemingly inability to end it despite repeated military operations. Sharif's pledge to halt the bloodshed through talks helped him get elected last year. Many Pakistanis blame the violence on the U.S. by saying that Pakistani militants are only attacking because the government is allied with the U.S., and once American troops leave Afghanistan, the attacks will stop. Many Pakistanis are angry at what they perceive to be a conflict pushed on them by the U.S. against fellow Muslims in the invasion of Afghanistan.

What is the security situation in Pakistan in general?

Even if the government is able to negotiate an end to the fighting with the Pakistani Taliban, it won't mean the end to violence in the country. The Pakistani Taliban is a loose affiliation of militant groups, and not all support the peace talks. There also are many other militants operating across Pakistan, including sectarian organizations that target the Shiite Muslim minority. Insurgent groups in the southwestern province of Baluchistan want an independent country.

What does Pakistan's fight against militancy show about its strength as a U.S. ally?

Critics have long said that Pakistan can't be a true U.S. ally because it has an ambiguous relationship with militants, fighting some of them — such as the Pakistani Taliban — and tolerating or supporting others that are considered useful foreign policy tools. Afghanistan has strongly criticized Pakistan, saying it gives sanctuary to militant groups in the tribal areas, where they have launched attacks on Afghanistan.